X Co. is a retail dealer of garden tractors. Mr. Y signs a contract to buy a garden tractor for $400, but later backs out of the agreement. The tractor that Mr. Y agreed to buy is subsequently sold to Mr. Z for $380.
The average cost of a garden tractor to X Co. is $260, and the average variable cost is $220.
The marginal cost to X Co. of supplying an additional tractor to a customer is $300. X Co. sues Mr. Y for breach of contract. How much damages should be awarded to X Co?